Vibration frequency and lock-in bandwidth of tensioned, flexible cylinders experiencing vortex shedding

Lee, L.; Allen, Don

doi:10.1016/j.jfluidstructs.2010.02.002

Cited by 35 publications

(17 citation statements)

References 11 publications

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“…Further experiments confirmed this argument [4]. Additional theoretical work on this subject has also been published [5,6]. Based on these developments, a new VIV design methodology is established and is presented in this paper.…”

Section: Introductionmentioning

confidence: 69%

A New VIV Design Procedure for Marine Tubular

Lee¹

2013

ASME/USCG 2013 3rd Workshop on Marine Technology and Standards

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Vortex-induced vibration (VIV) of a flexible structure is a hydro-elasticity phenomenon. In current VIV design of marine tubular, the effect of structural stiffness variations is not fully accounted for. A new design procedure for the VIV motions of the first mode is presented in this paper. Numerical examples indicate that this new method may provide a safer design. Paper published with permission.

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Section: Introductionmentioning

confidence: 69%

A New VIV Design Procedure for Marine Tubular

Lee¹

2013

ASME/USCG 2013 3rd Workshop on Marine Technology and Standards

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“…A recent study by Lee and Gerretsen [13] showed the importance of the effect of axial stiffness on tension change and VIV motion amplitude. Lee and Allen [14] concluded that top tension and structural stiffness can have a significant impact on vibration frequencies and lock-in bandwidth. They concluded that bending-dominated cylinders have a slight increase in vibration frequency after an abrupt rise to their first lock-in frequency because the motion of the structure takes control of the shedding process.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Shifting Natural Frequency on the Reduction of Vortex-Induced Vibrations of Marine Risers

Komachi¹,

Mazaheri²,

Tabeshpour

2017

ijcoe

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Many procedures suggest for reduction of responses of riser to Vortex Induced Vibrations (VIV). Natural frequencies of marine risers is an important parameter that can affect the responses of riser to VIV. Change of riser properties such as top tension and bending stiffness can alter natural frequencies. In this study effects of riser specifications on the responses and fatigue damage of marine risers were investigated analytically and numerically. For numerically analysis 2D wake-structure coupled model is used for modeling of VIV of riser in two directions of Cross Flow (CF) and In Line (IL). The wake dynamics, including IL and CF vibrations, is represented using a pair of non-linear Van der Pol equations that solved using modified Euler method. The Palmgren-Miner Rule is used for evaluation of fatigue damage. Riser of Amir-Kabir semisubmersible placed in Caspian sea is used for case study. Because VIV is self-limiting, it is showed that lower modes have lower curvature, that in some cases this is lead to lesser stress and also fatigue damage. The results show that for tension dominant modes of vibration, natural frequencies was increased with top tension and for a certain Strouhal frequency, dominant modes of vibration was reduced which leads to reduction of stress and fatigue damage. The results show that stress and fatigue damage increased with module of elasticity of riser and reduction of this leads to reducing of stress and fatigue damage. Therefore suitable procedure for reduction of VIV responses of riser should be selected based on the current velocity.

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“…Lee and Allen [14] noted that tensioned slender structures are classified into two types-beamlike (stiffnessdominated) and stringlike (tension-dominated) -by a dimensionless parameter, TL 2 /EI , where T is the tension, L is the structure length, and EI is the bending stiffness. If TL 2 is much greater than EI , then the structure is stringlike; otherwise, it is beamlike.…”

Section: Introductionmentioning

confidence: 99%

Effects of tension on vortex-induced vibration (VIV) responses of a long tensioned cylinder in uniform flows

Kang

Wei

et al. 2016

Acta Mech. Sin.

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The effects of tension on vortex-induced vibration (VIV) responses for a tension-dominated long cylinder with an aspect ratio of 550 in uniform flows are experimentally investigated in this paper. The results show that elevated tension suppresses fluctuations of maximum displacement with respect to flow velocity and makes chaotic VIV more likely to appear. With respect to periodic VIV, if elevated tension is applied, the dominant vibration frequency in the in-line (IL) direction will switch from a fundamental vibration frequency to twice the value of the fundamental vibration frequency, which results in a ratio of the dominant vibration frequency in the IL direction to that in the cross-flow direction of 2.0. The suppression of the elevated tension in the fluctuation of the maximum displacement causes the axial tension to become an active control parameter for the VIV maximum displacement of a tension-dominated long riser or tether of an engineering structure in deep oceans. However, the axial tension must be optimized before being used since the high dominant vibration frequency due to the elevated tension may unfavorably affect the fatigue life of the riser or tether.

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Vibration frequency and lock-in bandwidth of tensioned, flexible cylinders experiencing vortex shedding

Cited by 35 publications

References 11 publications

A New VIV Design Procedure for Marine Tubular

A New VIV Design Procedure for Marine Tubular

The Effect of Shifting Natural Frequency on the Reduction of Vortex-Induced Vibrations of Marine Risers

Effects of tension on vortex-induced vibration (VIV) responses of a long tensioned cylinder in uniform flows

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